The brief
William's C180 came in for its regular service, and on a higher-mileage car the starter motor is one of the components worth keeping an eye on, it does its work every single start. The check found this one starting to draw badly, so it was changed while the car was in. A service runs through the whole car, oil and filters, fluids, brakes, suspension, electrics, a scan, and on a car with miles on it the starter gets a closer look. The starter is the electric motor that spins the engine over fast enough to fire, with brushes, a solenoid and bearings that wear, and a starter on its way out cranks slowly, whirrs, or eventually doesn't engage at all. Caught at the drawing-badly stage it's a planned change rather than a roadside no-start, so it was the service plus a starter motor.
The diagnosis
The service check went through everything. The engine oil and filter were due, the air and cabin filters near the end, a couple of fluids wanting topping, and the starter draw test showed it pulling badly and not engaging as crisply as it should, on its way out on a higher-mileage car. The brakes, belts, hoses and underbody checked out, no fault codes stored. So it was a service plus a starter motor replacement: the wear items refreshed, the fluids freshened, a fresh starter before it could leave William stuck.
The work
The engine oil was drained and refilled with the correct Mercedes-spec oil and a new oil filter fitted, the air and cabin filters replaced, the fluids topped, and a full diagnostic scan run. The old starter motor was removed and a new genuine Mercedes-spec starter fitted, the wiring and the earth checked and reconnected cleanly, every fastener torqued to spec, and the engine cranked and started to confirm a strong, clean crank. A road test confirmed a clean start, steady running, and nothing leaking.
The outcome
A clean bill of health on the C180, fresh oil and filters, fluids topped, a clean scan, and a strong, clean crank on a fresh starter. The car went home serviced and sorted. A starter on its way out ends in a no-start, so catching it during the service and changing it before it failed headed that off, the kind of thing the inspection is for on a car with miles on it.